through the operation
and the power of the Life Force within it. In the human body it is
through the instrumentality of the cell that this process is going on.
The cell is the ultimate constituent in the formation and in the life of
tissue, fibre, tendon, bone, muscle, brain, nerve system, vital organ.
It is the instrumentality that Nature, as we say, uses to do her work.

The cell is formed; it does its work; it serves its purpose and dies;
and all the while new cells are being formed to take its place. This
process of new cell formation is going on in the body of each of us much
more rapidly and uniformly than we think. Science has demonstrated the
fact that there are very few cells in the body today that were there
twelve months ago. The form of the body remains practically the same;
but its constituent elements are in a constant state of change. The
body, therefore, is continually changing; it is never in a fixed state
in the sense of being a solid, but is always in a changing, fluid state.
It is being continually remade.

It is the Life, or the Life Force within, acting under the direction and
guidance of the subconscious or subjective mind that is the agency
through which this continually new cell-formation process is going on.
The subconscious mind is, nevertheless, always subject to suggestions
and impressions that are conveyed to it by the conscious or sense mind;
and here lies the great fact, the one all-important fact for us so far
as desirable or undesirable, so far as healthy or unhealthy, so far as
normal or aging body-building is concerned.

That we have it in our power to determine our physical and bodily
conditions to a far greater extent than we do is an undeniable fact.
That we have it in our power to determine and to dictate the conditions
of "old age" to a marvellous degree is also an undeniable fact--if we
are sufficiently keen and sufficiently awake to begin early enough.

If any arbitrary divisions of the various periods of life were
allowable, I should make the enumeration as follows: Youth, barring the
period of babyhood, to forty-five; middle age, forty-five to sixty;
approaching age, sixty to seventy-five; old age, seventy-five to
ninety-five and a hundred.

That great army of people who "age" long before their time, that
likewise great army of both men and women who along about middle age,
say from forty-five to sixty, break and, as we say, all of a sudden go
to pieces, and many die, ju